In the development of philosophical thought in India there are two main currents, the Vedic and the non-Vedic. It is true that since early mediaeval times the Vedas have been regarded as the source of all Indian wisdom, but this was possible only by interpreting the term Vedas in a very wide sense. Agama-Sastras and sciences and arts, like medicine and music, were accepted as parts of the Vedas, though they could not be traced to any extant text of the Vedas.
Nothing definite can be said as to whether Hindu thought is the result of the addition of the Aryan or the Vedic elements to an earlier Dravidian civilization or the addition of Dravidian elements to an already existing Aryan or Vedic civilization. This much is certain, that what is called Hindu is not a simple growth from Aryan or Vedic civilization. The element other than the Aryan or the Vedic, which contributed to this development, will be described here as Dravidian. This Dravidian element is the most important other element in Hindu thought and the other non-Vedic elements may therefore be ignored.
It is difficult to define what is meant by the term Dravidian. The term is applied to a group of languages, to a people, and also to a civilization. The languages that are Dravidian have preserved their individuality, though mixed up with the Aryan languages. The ethnic inter-mixture in India has been so great that it is not possible at present to say who are the Dravidian peoples. Similarly, it is difficult to define Dravidian civilization, as distinct from the Aryan or Vedic civilization. Linguistic and ethnic surveys make it clear that it is wrong to think of North India as wholly Aryan and South India as wholly Dravidian. Linguistically, this division is not very wrong, but various minor languages spoken in North India show pronounced Dravidian elements. All that can be done is to mark out features in Indian thought which cannot be traced back to the Vedas as direct and natural developments from Vedic texts and treat them as Dravidian in this broad sense.
The part played by the forest in the evolution of Indian thought has deservedly received recognition in modern times. The asramas of the rishis were the centres for the development of philosophical thought in India, but only from the time of the Upanisads. Forests played no part in the pre-Upanisadic Vedas. The Rig-Vedic rishis were citizens living in cities and villages, and not people who retired to the forest for contemplation.
The forest plays no part in the civilization of the Brahmanas either. In the Taittiriya-Aranyaka there is, however, a reference to obligatory study being in a place other than the village and the home. The place is described as one from which there will not be the sight of the roof of the homes. The distinction of the two parts of the obligatory study as what could be done in the village (gramya) and what should be done in the forest (aranya) is very clear in the later literature of the Vedas relating to the life of the Hindus. The gods of the Vedas are not forest deities. They came in chariots drawn by horses and there is no mention of hunting associated with the Vedic gods. But when we come to the non-Vedic gods of Hinduism, we find that they are associated with the forest and with hunting.
Nearly all the Shaiva gods of Hinduism are non-Vedic, and are recognized as Dravidian. There are especially two deities, Kali or Durga and Ayyappan (a Dravidian god that is supposed to be the offspring of Shiva through Vishnu as Maya, who distributed nectar to the gods after the churning of the ocean). The temple of these two deities is called a kavu in certain parts of South India and the word means a forest or grove. This shows that these deities were worshipped in forests and groves. The place where the serpent images are installed and worshipped is also designated by the same term.
The influence of the non-Vedic element was not merely in introducing a new kind of scene for the development of thought in the country, but also in bringing about a change in the approach to the problem of truth.